Our current leader suffer the same weakness as our past leaders: Failure to foresee the consequences of their preferred (and tested) strategies in new environments.
The First World War as practically fought as a classic European war initially. And it was assumed by everyone that it would be just that; another quick decisive war. And it looked like it might almost have been that, had it not been for some strategic blunders by German HQ. Blunders that were sparked by conservative ideas and classic defence strategy.
When the war became entrenched, no side truly knew how to advance. They knew how to defend their position (machine guns), but not how to take the other's positions. That first really changed with the introduction of the tank. But that arrived too late to partake in many battles in that war. The Second World War proved its usefulness to its fullest.
Traditional geopolitical, strategic thinking and military schools turned the First World War into a far bloodier than it could have been. New technology, new warfare tactics among other things have changed they dynamic for war.
Today, new ideologies, again new warfare tactics (think urban warfare), new opponents (not nation states anymore) among other things are again changing the dynamic.
When the First World War ended, the solution to it was the same as always; war reparation without considerations to their consequences. The same thing is happening today; old strategy and military schools are being applied to conflicts to which they do not apply.
It might be because our current leaders are politicians first, and need to secure their popularity among voters. Moreso than our past leaders. But it might also just be history repeating itself. In a way.
Europe has historically had long, drawn out wars that wiped out huge swathes of the civilian population. https://en.wikipedia.org/wiki/Thirty_Years%27_War
About 2M refugees in 2015 (highest number I could find) into a population of ~508M isn't "flooding". For comparison, there seems to have been just over 5M "live births" in 2014[3].
[1] http://www.bbc.co.uk/news/world-europe-24583286 [2] http://ec.europa.eu/eurostat/web/population-demography-migra... [3] http://www.statista.com/statistics/253401/number-of-live-bir...
Mohammed is the most popular baby name in London. The young-adult-male cohort in Germany will soon be dominated by peoples of Middle Eastern origin - most Germans are old, and immigrants are largely young and male. In countries like Sweden, fully 20% of the population is foreign-born or born to foreign-born parents. Cultural change is definitely coming to the EU one way or another. For hundreds of years, until around the 60s, most European countries allowed virtually no non-European immigration. Given the birthrates of native Europeans, we're talking about total demographic replacement in a few generations in many countries. I find it hard to believe that's not going to cause some instability in the short to medium term.
And I'm glad this is the case. A war between any of the great powers could potentially have catastrophic consequences for almost everyone.
> Remember, the powers that were were rather equal in terms of military strength. Today, they team up to beat on weaker powers.
Maybe this seemed like a acceptable strategy back in the 90ties, but today we see it backfiring on everyone.
Refugees flooding the EU causing EU members to block each other which in turn threatens the EU itself, radicalised Muslims threatening the territorial integrity of China, North Korea going nuts, possibly a bloody civil war awaiting Turkey.
My point is that you can gang up and beat on weak players only for so long until the masses radicalise and become a major threat to your own existence.